From Wikipedia, the free encyclopedia

A security increase often occurs when a nation, state, or
institution has recently suffered from a serious incident or is
under the perception that there is an increased risk for an
incident to occur that endangers or potentially endangers its
well-being.

Historically, security
has been increased by governments and private institutions for a
variety or reasons, including incidents that have occurred to
themselves, to other similar institutions, or to the world, nation,
or region following a high-profile event or a perceived threat of
one. When this occurs, many identify the move as elevated,
heightened, or "beefed-up" security.

Those who are forced to make changes or be extra-vigilant as a
result or the increase sometimes refer to the new era as the
"security age."

September
11 attacks

Following the attacks of September 11, 2001, numerous measures
were by the United
States and other countries to increase security in many
settings. Soon after, the United States launched the Department of Homeland Security.